1. Technical Field
The present disclosure relates to a catheter assembly, and, in particular, relates to a hemodialysis catheter adapted to facilitate bidirectional fluid flow.
2. Description of the Related Art
Catheters are flexible medical instruments intended for the withdrawal and introduction of fluids relative to body cavities, ducts and vessels. Catheters have particular application in hemodialysis procedures where blood is withdrawn from a blood vessel for treatment and subsequently returned to the blood vessel for circulation. Known hemodialysis catheters include multiple lumens, such as dual lumen or triple lumen catheters, permitting bi-directional fluid flow within the catheter whereby one lumen is dedicated for withdrawal of blood and the other lumen is dedicated for returning the treated blood to the vessel. During an exemplary hemodialysis procedure, a multiple lumen catheter is inserted into a body and blood is withdrawn through an arterial lumen of the catheter. The removed blood is directed to a hemodialysis unit which dialyzes, or purifies, the blood to remove waste and toxins. The dialyzed blood is returned to the patient through a venous lumen of the catheter.
Conventional hemodialysis catheters incorporate various catheter tip designs, such as a staggered arterial (inlet) and venous (outlet) design, to ensure blood returning to the patient will be expelled downstream from the arterial inlet which is located upstream to draw the blood from the subject. Unfortunately, poor flow performance is a common problem with hemodialysis catheters, typically, due to occlusion resulting from fibrin sheath formation, thrombus formation and positional occlusion. Flow occlusion is primarily caused by blockage of the arterial lumen. Resolving poor flow is required to deliver the dialysis treatment to the patient. Current measures taken to resolve flow occlusion include repositioning the patient, flushing the lumens and reversing the blood lines of the catheter to the hemodialysis unit. This, however, creates a situation where cleaned blood is expelled upstream relative to the catheter inlet, which undesirably increases the potential for clean blood to be drawn back into the catheter resulting in “recirculation” of the blood. “Recirculation” creates inefficient dialysis by increasing treatment time to reach prescribed blood cleanliness levels.